A cobalt-pyrrole coordination compound as high performance cathode catalyst for direct borohydride fuel cells

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient catalysts for oxygen reduction reaction (ORR) is crucial for clean energy technologies.
• Cobalt-based catalysts coordinated with nitrogen-rich polymers show promise for electrochemical applications.
• Macroporous carbon (MPC) provides a high surface area support for catalytic materials.

Purpose of the Study:

• To synthesize a novel cobalt-pyrrole/MPC catalyst using a dinitratobis(polypyrrole)cobalt(ii) precursor.
• To investigate the role of long-chain coordination structures in enhancing catalytic activity.
• To evaluate the catalyst's performance in alkaline ORR and direct borohydride fuel cells (DBFCs).

Main Methods:

• Synthesis of dinitratobis(polypyrrole)cobalt(ii) adduct from pyrrole and cobalt nitrate.
• Formation of the Co-pyrrole/MPC catalyst precursor with abundant Co-N bonds.
• Electrochemical characterization of the catalyst's ORR activity and DBFC performance.

Main Results:

• The Co-pyrrole/MPC catalyst exhibited high ORR catalytic activity in alkaline media.
• A peak power density of 325 mW cm⁻² was achieved in a DBFC at ambient conditions.
• The catalyst outperformed a commercial Pt/XC-72 benchmark.

Conclusions:

• The long-chain coordination structure of the precursor is key to the enhanced electrochemical performance.
• The Co-pyrrole/MPC catalyst offers a promising alternative to platinum-based catalysts for DBFCs.
• This synthesis strategy provides a pathway for developing advanced catalysts for fuel cell applications.